The long range purpose of this project is to understand the role that extracellular matrix macromolecules play in various aspects of oral-facial development and to understand the regulation of cellular proliferation and differentiation in these tissues by: (1) defining the biochemical nature of the factors that regulate the differentiation of cranial neural crest cells, (2) determining the biochemical nature of the surface glycoproteins that are involved in secondary palatal adhesion, (3) determining the biochemical events that regulate programmed cell death of palatal epithelial cells; (4) determining the difference in glucocorticoid receptor proteins from embryos and mesenchyme cells of mice which differ in their sensitivity to glucocorticoid-induced cleft palate, and (5) determining the biochemical nature of the defect present in the cartilage of the short limb Brachymorphic mouse.